The invention refers to a temperature-measuring sensor with an electronic circuit to choose the characteristic required by the respective measuring purpose.
Such temperature-measuring sensors are used in a wide range of applications, such as for controlling. Temperature-dependent controls are performed with such temperature-measuring sensors that measure a certain temperature and convert the measured value into a signal, which can be used to operate controls and control loops.
For example, sensors play an important role in the steel industry, where they detect warm roll material. Such devices are used in large numbers in any given rolling mill. Typical tasks of such devices include the initiation of the separation process in extrusion-casting equipment when the desired extrusion length has been reached. Other tasks are controlling scrap scissors and cowls, to name but a few.
While being processed, the roll material to be detected being transported by roller conveyors that heat up over time and may assume temperatures of 300xc2x0 C. or more. The roll material itself has a temperature of more than 1,000xc2x0 C. at the beginning of the rolling process, and cools down to less than 250xc2x0 C. at the end of the rolling train.
The task of the sensors described herein is to detect the warm roll material, but not the background temperature.
In order to make this possible, the sensors described above are manufactured with various response temperatures. One proven concept for these response temperatures is scaled, for example, 250xc2x0 C., 350xc2x0 C., 450xc2x0 C., 650xc2x0 C. and 800xc2x0 C.
In this manner, it is possible to choose the device with the right response temperature for every task. Al the beginning of the rolling process, the roll material has a temperature of approx. 1,000xc2x0 C. A device with a response temperature of 450xc2x0 C. would properly detect the roll material, but also the background temperature of the roller conveyor, which was heated up by the high temperature of the roll material. A device with a response temperature of 800xc2x0 C. would be appropriate.
The solution described abovexe2x80x94the production of devices with various response temperaturesxe2x80x94may work, but would require such a rolling mill to have devices in stock for each of the present response temperatures. In order to reduce excessive stock keeping and to achieve a higher degree of flexibility when deploying such devices, there are devices that allow the user to choose a response temperature. This choice is made possible by making available several response temperatures, which can be selected by a certain configuration of the connection cable or of the connector. With this measure, stock keeping is reduced. However, this solution has a number of grave practical flaws.
Trouble-free operation of these devices is of critical importance to the operation of a rolling mill. For this reason, it must be ensured that the selected response temperature cannot be changed arbitrarily. However, the devices described above are not safe from such change. This is why there is great danger that the selected response temperature is changed by unauthorized persons, which can have grave consequences.
Therefore, the object of the present invention is to provide a temperature sensor that offers a choice of response temperatures without featuring the disadvantages described above.
According to the invention, this object is accomplished by incorporating a microprocessor or equivalent in the electronic circuit, which allows the characteristic to be programmed.
By contrast to the known embodiments with response temperatures permanently set by the electronic circuit, such embodiment offers significant advantages: the response temperature can be programmed with the aid of appropriate software; i.e., it can be changed at will, within the scope of technical possibilities without having to change the electronic circuit itself. This allows precise adjustment of the response temperature of such devices to the differing requirements of a rolling train to an extent not possible with previously known equipment.
By virtue of the invention described above, which lends itself to continued development corresponding with the progress of microprocessor technology, the current state of the art is advanced by a critical step, and the possibilities of application for these devices are considerably extended by making it possible for them to be programmed to adapt to the intended change.
Another area of application using the same principle is temperature-measuring devices. In such devices, both the temperature range to be measured and the dissolution or scaling of the measured value can be programmed. The devices designed in conjunction with the invention, therefore, are universal devices that may be used to accomplish a wide range of various temperature-measuring tasks, but can also be designed as special devices configured to suit the individual task at hand by virtue of their programmability.
According to a preferred embodiment of the invention, the temperature-measuring sensor is designed as a heat-radiation sensor. The principle embodied by the invention lends itself particularly well to the measuring of heat radiation, because it is installed at a physical distance from the radiating body. The trouble factors that may occur at this physical distance, such as changing current conditions, are best compensated by a temperature-measuring sensor working in accordance with the principle embodied by the invention.
However, according to another embodiment of the invention, the temperature-measuring sensor can also be designed as a heat-conduct sensor, which can compensate changing factors in the area of heat conduct in a favorable fashion.
According to another preferred embodiment of the invention, the electronic circuit is equipped with an output switch that emits a switch signal when the peak value has been reached. This switch signal is used for controlling purposes. For example, mechanic controls can be switched on and off with it.
In another preferred embodiment of the invention, programming of the characteristic is focused on determining and storing a peak value. In this manner, it is possible, for example, to obtain important statistical data about the development of the temperature, which may be used to improve the production process.
According to another preferred embodiment of the invention, programming of the characteristic can be focused on identifying the base value and a value differential exceeding the base value. With the aid of this characteristic, which becomes effective upon appropriate programming of the temperature-measuring sensor, the roll material can be sorted according to the identification of a certain value differential. In this manner, the production quality can be improved.
According to another preferred embodiment of the invention, the output signal can be either binary or measuring, depending on the program selected. By using the appropriate software, the area of application for the temperature-measuring sensor can be expanded significantly and adapted to the task at hand.
According to another preferred embodiment of the invention, the development of the temperature over time can be programmed. In this manner, it is possible to tie the emission of an output signal prompted by a certain measured temperature to the development of the temperature over time.
According to another preferred embodiment of the invention, the software can he adapted to a temperature profile of a certain warm material to be detected. In this manner, it is possible to program the temperature-measuring sensor in such way that it emits an output signal only if a temperature profile measured matches a certain pre-programmed value.
According to another preferred embodiment of the invention, a mean temperature value can be determined over a programmable period of time. Only if the mean value measured in this manner matches a pro-programmed value, the temperature-measuring sensor emits or does not emit, an output signal.